Endoscopic, laboratory, and clinical findings and outcomes of caustic ingestion in adults; a retrospective study

Aim: Compared to the prevalence and complications, there is still limited evidence in this regard. Background: With an incidence rate of 200,000 cases annually and the induction of numerous complications, caustic ingestion imposes a significant burden on the healthcare system. Apart from being fatal in some cases, this injury affects its victims’ quality of life as it is followed by many gastrointestinal problems. This injury mainly occurs accidentally among children, whereas in adults, it often occurs with suicidal intentions. Despite recent advances in internal medicine, gastroenterology, and toxicology, this type of injury remains a debilitating and, in some cases, fatal disorder for its victims. Methods: This study retrospectively evaluated the clinical, laboratory, and endoscopic findings of 150 patients admitted to a referral center of toxicology and forensic medicine and assessed factors associated with each type of injury. Results The findings indicated a mortality rate as high as 7.3% in this population. Age, pH, and previous medical conditions were associated with more complications. Higher degrees of injury were also significantly associated with higher mortality. No significant difference was observed between types of corrosive substances. Conclusion: It seems that the most effective intervention for controlling caustic ingestion injuries would be psychiatric support, primary healthcare, and household education.


Introduction
1 Corrosive or caustic substances are chemicals that harm tissue in case of exposure. Although the most frequently affected organs are the face, eyes, and extremities, mortal cases are highly frequent following caustic ingestion (1,2). According to the American Association of Poison Controls, more than 200,000 corrosive ingestions occur annually, commonly caused Caustic ingestion usually induces one of two types of injuries, acute or chronic. Acute phase injury includes inflammation, necrosis, and gangrene, and in this situation, medical interventions mainly control the perforation, secure the airway, provide fluid resuscitation, and manage the possible shock (6). However, the chronic phase involves bleeding, fibrosis, and strictures, and interventions aim to correct the stenosis, repair the formed fistulas, and manage the ingestion disorders following esophageal movement disorders and management of the esophageal diverticulitis (7). In cases of gastrointestinal perforation (e.g., mediastinitis, peritonitis), urgent surgery is indicated; otherwise, management is primarily based on the findings of an esophago-gastro-duodenoscopy procedure and, in some cases, endoscopic ultrasound (EUS) or abdominal computed tomography (CT) scan to evaluate the depth of the injury (8). Despite recent advances in primary healthcare, toxicology, and gastroenterology, caustic injuries and the morbidity and mortality caused by them are still a significant issue in toxicology, surgery, and internal medicine wards. This study evaluated the demographic features and clinical manifestations of patients who ingested corrosive substances as well as the substances' contribution to the mortality of patients admitted to a referral center for toxicology, internal medicine, surgery, and clinical forensic medicine in one year.

Methods
The medical records of patients admitted to a referral center for internal medicine, surgery, medical toxicology, and clinical forensic medicine, who underwent endoscopy during their admission following caustic ingestion in one year were evaluated. After applying the inclusion and exclusion criteria, 150 patients were included in this study. The evaluated parameters included age, sex, caustic substance type and amount ingested, cause of ingestion, ingestionadmission interval, and laboratory tests.
The endoscopic studies were performed by a single board-certified professor of gastroenterology with more than ten years of clinical, educational, and research experience, and the clinical records of other operators were excluded from the study.

Inclusion criteria
 Ingestion of caustic substances  Undergoing endoscopy during admission  Complete and consistent medical records  Patient's consent Exclusion criteria  Incomplete medical records  Caustic injury without ingestion of the caustic substance  Patient's refusal to participate in this study

Informed consent
Informed consent to use their clinical, laboratory, and unidentified personal data for publication and scholar purposes was obtained from all individual participants included in the study.

Statistical analysis
Data was analyzed by descriptive statistics, t-test, and chi-squared test using (SPSS 26; IBM SPSS Statistics) and reported in tables. Statistical significance was set at p≤0.05.

Demographic findings
Of 150 patients, 52.7% were female and 47.3% were male; 19.3% of patients were younger than 20 years of age, 47.3% and 33.3% were 21-40 and >41 years of age, respectively, and 32.7% of all patients had a history of medical conditions ( Figure 1).

Features of the caustic injury
As shown in Table 1, 40.7% of patients had no pathological findings in their endoscopic study. However, 36%, 19.3%, and 4% of the patients had first-, second-, and third-degree burns in their gastrointestinal tract. Of all injuries, 32% were caused by sodium hypochlorite (NaOCl) solution, followed by depilatory agents, hydrochloric acid, sulfuric acid, drain cleaner, sodium hydroxide, paraquat, and other corrosive substances (e.g., hydrogen peroxide, carpet cleaning shampoo, dishwasher tablets, and washing powders) as the less prevalent causes of injury. Based on the notes documented in the patients' medical files and regarding the pH of the substances, 44.7% were acidic, 43.3% were alkaline, and the pH of 12% of the substances was unknown and unrecorded. Seventy-two percent of the ingestions were intended to commit suicide, and 70.7% were performed between 12 pm and 12 am. Moreover, 48.5% of cases were admitted to the center <2 hours after ingestion, 40.7% were admitted between 2 to 6 hours, and 11.3% were admitted into our center >6 hours after the caustic ingestion incident. Additionally, 41.3% of patients had one or two complaints, whereas 58.7% complained of more than two clinical conditions. Among all participants, 68.7% had abnormal laboratory tests, and 7.3% of all patients died during their hospital stay. The most prevalent manifestations of the studied cases were parallel skin injuries and abdominal pain (Table 1), and the most prevalent objective finding was epigastric tenderness. Nonetheless, the highest mortality rate was observed in the bleach group (12.5% of cases) and acidic substances overall (10.4% of cases).
Furthermore, 35.3%, 37.3%, and 21.3% of patients had esophageal, gastric, and duodenal injuries as revealed by endoscopy. As shown in Tables 2, 3, and 4, advancing age significantly correlated with the esophageal, gastric, and duodenal injury (p<0.05). Additionally, previous medical conditions made the patients more susceptible to gastric injuries (p<0.05).

Expired patients
Of all the 150 patients assessed herein, 11 cases (i.e., five women and six men) died. As shown in Table  5, no significant associations were found between mortality, sex, age, previous medical history (PMH), site of injury, ingestion-admission period, laboratory tests, and type of abused corrosive substance. However, higher grades of injury were significantly associated with a greater risk of mortality among cases. All of the expired patients had a 2nd or 3rd degree injury, and the mortality rate of patients with normal or first-degree injury endoscopic findings was zero. Moreover, among reported presenting signs and symptoms, dysphagia and pulmonary rales were significantly associated with increased risk of mortality among patients.

Discussion
Ingestion of caustic agents usually occurs accidentally among children (9, 10); however, in case of adults, as in the present study, ingestion is usually associated with suicidal intentions. This type of suicide is more prevalent among women than men and causes acute and chronic complications. Mortality following caustic ingestion is as high as 5-10% (11), consistent with the present study, in which mortality was calculated at 7.3%.
According to the literature, the most abused substance in cases of caustic injuries is toilet cleaner, which contains strong acid of alkali (12,13). However, in the current study, the most commonly abused substance was bleach (sodium hypochlorite). Accordingly, the highest mortality rate was observed in the bleach group.
There are still many controversies regarding the association between presenting signs and symptoms and poor prognosis (12). Drooling of saliva and sialorrhea have been reported as the predictors of higher grades of mucosal injury (13). In the present study, dysphagia and pulmonary rales were significantly associated with a greater risk of mortality, though no significant association was found between presenting signs and symptoms and the grade of injury.
In the present study, anemia was the most prevalent laboratory finding among the patients, which could be considered endemic prevalent anemia and/or gastrointestinal bleeding. Second to anemia, leukocytosis is the most reported laboratory finding among cases, consistent with the present study, and might be attributed to inflammation and stress. Additionally, as in the literature (1,4), esophageal injuries were the most prevalent, followed by gastric and duodenal wounds.
Age, pH, and previous medical conditions were associated with more complications, and it seems that the most effective intervention for controlling these types of injuries would be psychiatric support, primary healthcare, and household education. As mentioned above, a significant number of cases had undergone improper interventions before coming to the center and being admitted. To address this error, it is recommended that continuous educative materials be provided for both ordinary members of society and members of medical care teams. Moreover, a higher degree of injury was significantly associated with higher mortality. However, in the literature, injuries of a higher degree were significantly associated with the abused substances' pH. In the present study, no significant difference was observed between types of corrosive substances; however, the pH of substances was not evaluated.
All the expired patients had a 2nd or 3rd degree injury, and the mortality rate of patients with normal or first-degree injury endoscopy findings was zero. Overall, the current findings are consistent with those of previous studies. Nonetheless, more standardized studies with a larger sample size and control cases are strongly recommended.